This K23 proposal combines focused coursework and training, a thoughtful research plan and an expert mentoring team and is designed to foster the development of Kerri Thom, MD, MS into a successful, independent investigator in the study of emerging infections and antibiotic resistance. Dr. Thom proposes to study the hospital epidemiology of Acinetobacter baumannii. This organism has emerged as an important cause of nosocomial infections due to a rising incidence, associated morbidity and mortality and the rapid development of multidrug resistance. In Aim 1, Dr. Thom will identify Acinetobacter colonization among a large, existing cohort and will use molecular typing to quantify the amount of patient-to-patient transmission in the endemic setting. Aim 3 will also utilize this cohort to examine the association between environmental contamination and subsequent nosocomial transmission. In Aim 2, Dr. Thom will prospectively identify a cohort of patients infected with Acinetobacter to determine the rate of contamination of the surrounding environment and to identify heavily contaminated sites. This research will lead to an improved understanding of the hospital epidemiology of Acinetobacter, including the modes of transmission and the role of the environment in nosocomial spread, which will be essential in the development of cost-effective interventions aimed at decreasing transmission. This K23 award will provide Dr. Thom with the opportunities for specific training in molecular epidemiology, antimicrobial resistance mechanisms and research informatics which will be essential to the success of this proposal and to her future success in patient-oriented research in emerging pathogens and antimicrobial resistance. To help achieve these goals, she has assembled a mentoring team with a wealth of experience: Drs. Harris (emerging pathogens/antibiotic resistance, research informatics), Stine (molecular epidemiology, bioinformatics), Roghmann (emerging pathogens/antibiotic resistance, molecular epidemiology), Magder (biostatistics), Bonomo (antibiotic resistance mechanisms), and Srinivasan (Outbreak investigation of Acinetobacter). The support of this K23 award will provide the experience and training needed to compete for R01 NIH grant funding and will serve as a foundation for a career as an independent investigator and a leader of emerging pathogens and antibiotic resistance.